The most common form of a sealed-tube manometer is the conventional mercury barometer used to measure atmospheric pressure. A
manometer can be designed to directly measure absolute pressure
. The manometer in Figure 5 measures the pressure compared to zero absolute pressure in a sealed leg above a mercury column.
How do you measure atmospheric pressure?
Atmospheric pressure is commonly measured with
a barometer
. In a barometer, a column of mercury in a glass tube rises or falls as the weight of the atmosphere changes. Meteorologists describe the atmospheric pressure by how high the mercury rises.
What does a manometer do?
A manometer is an
instrument used to measure and indicate pressure
. There are two types of manometers, analog and digital.
What devices measure atmospheric pressure?
A barometer is a scientific instrument used to measure atmospheric pressure, also called barometric pressure.
Can manometer measure low pressure?
Pressure is defined as a force per unit area – and the most accurate way to measure low air pressure is
to balance a column of liquid of known weight against it
and measure the height of the liquid column so balanced.
What fluid is used in a manometer?
The open-end manometer (Fig. 4.4a) is a glass tube, usually U-shaped, filled with the manometer fluid
(mercury or oil)
(see Section 3.2).
What is a good manometer reading?
The readout on the manometer should be
between 0.5in – 1.75in.
In most cases these are acceptable levels indicating, your system is operating correct. When your Radon system is shut off the fluid should rest at zero if it does not then your manometer is low on fluid.
What are the two types of pressure?
There are two basic pressure types:
absolute and gauge
, distinguished by what pressure they are compared to, which is called the reference pressure.
What are two factors that affect air pressure?
- Temperature.
- Altitude or Elevation.
- Moisture ow water vapour.
What is the standard unit of air pressure?
It corresponds to the pressure exerted by a vertical column of mercury (as in a barometer) 760 mm (29.9213 inches) high. One standard atmosphere, which is also referred to as one atmosphere, is equivalent to
101,325 pascals
, or newtons of force per square metre (approximately 14.7 pounds per square inch).
What type of manometer is best for measuring low pressure?
Low pressure and low differentials are better handled with
an inclined-tube manometer
, where 1 in. of vertical liquid height can be stretched to 12 in. of scale length. Liquid manometers measure differential pressure by balancing the weight of a liquid between two pressures.
What is the manometer equation?
Manometers. One of the most important classes of pressure gauges applies the property that pressure due to the weight of a fluid of constant density is given by
p = hρg.
What are the types of manometer?
- U-Tube Manometer.
- Differential U-Tube Manometer.
- Inverted U-Tube Manometer.
- small Manometer.
- Inclined Manometer.
What makes a good manometer fluid?
Several properties of a manometric liquid, such as vapor pressure,
density dependence on temperature, pressure and gas saturation
, viscosity and capillary properties, have an effect on the performance of the liquid column manometer and on the achievable uncertainty.
What is the difference between a manometer and a barometer?
In a close-ended manometer, one end of the manometer is attached to the
high-pressure gas
, and the other has a vacuum of gas instead of being open to the air. Barometers also fill this function, but measure only atmospheric gases. Barometers are usually filled with mercury.
